Ex 13.2, 9 - Chapter 15 Class 11 Statistics (Important Question)
Last updated at April 16, 2024 by Teachoo
Chapter 15 Class 11 Statistics
Chapter 15 Class 11 Statistics
Last updated at April 16, 2024 by Teachoo
Ex15.2, 9 Find the mean, variance and standard deviation using short-cut method Mean(𝑥 ̅) = A + (∑▒𝑓𝑖𝑦𝑖)/(∑▒𝑓𝑖) ×ℎ where A = assumed mean = 92.5 𝑦_𝑖=(𝑥_𝑖 − 𝐴)/ℎ h = class size = 75 − 70 = 5 Variance (𝜎)2 = ℎ2/N2 [𝑁∑▒𝑓𝑖𝑦𝑖2 − (∑▒𝑓𝑖𝑦𝑖)^2 ] = 52/602 [N × (254) – (6)2] = 25/3600 [60 ×254 −36] = 25/3600 × 15204 = 105.58 ∴ Standard deviation (𝜎) = √Variance = √105.58 = 10.27